Relieving slide-valves of pressure



1%. 34,259, ,PATENTED JAN. 28, 1862.

J. MARTIN. RELIEVING SLIDE VALVES OP PRESSURE.

m. mwus nuns cu. FNUTO-UTHO, WASHINGTON. n c

JACOB MARTIN, OF

MOUND CITY,

ILLINOIS.

RELIEVING SLIDE-VALVES OF PRESSURE.

Specification of Letters Patent No.

To all whom it may concern:

Be it known that I, JACOB MARTIN, of Mound City, in the county ofPulaski and State of Illinois, have invented a new and usefulImprovement in the Relief of the Slide-Valves of Steam-Engines fromUnnecessary Pressure; and I do hereby declare that the following is afull, clear, and exact description of the same, reference being had tothe accompanying drawings, forming part of this specification, in whichFigure 1, is a longitudinal section of a valve chest and valveillustrating the application of my invention. Fig. 2, is a transversesection of the same.

Similar letters of reference indicate corresponding parts in the twofigures.

This invention relates to the connection of the slide valve with apiston which is fitted to an open cylinder in the back of the valvechest and upon which the pressure of the steam acts in opposition to itspressure on the back of the valve; and it consists in combining thevalve With the piston by means of a roller attached to the valve and astraight bar attached by a yoke to the piston.

To enable others skilled in the art to fully understand and use myinvention I will proceed to describe its construction and operation.

A, is the valve chest.

13, is the slide valve of ordinary construction.

a, e. is the seat.

C, is the cylinder formed in or attached to the back of the chest A,open at its inner end to the steam chest and its outer end to theatmosphere.

D, is the piston fitted to the cylinder C, with metallic packing andhaving rigidly secured in it a concentric rod E, which Works in a guidein a bar F, arranged across 34,259, dated January 28, 1862.

the top of the cylinder and bolted to the sides thereof.

G, is the roller attached to the back of the valve by means of twobearings a, a, which are secured rigidly to the valve and which receivethe journals of the axle b, of the roller.

H, is the straight bar upon which the roller runs, secured rigidly tothe piston D by means of the yoke I. The edge or side of this bar uponwhich the roller runs is parallel with the valve seat. The said edge isrepresented of V-shape but it may be flat or of any other shape, theperiphery of the roller being of a shape to correspond.

The area of the bore of the cylinder C, should bear such proportion tothat of the face of the valve, say about seven eighths. that the upwardpressure of the steam upon the piston should so far counteract that uponthe valve as to leave just suflicient excess of pressure upon the valveto overcome any pressure in the engine cylinder on the exhaust side ofits working piston and so prevent the displacement of the valve andconsequent leakage.

In the Working of the valve the roller runs freely upon the bar H, andso relieves the valve of pressure to the extent due to the pressure uponthe piston D, and hence the valve works with very slight friction.

What I claim as my invention and desire to secure by Letters Patent, is;

Combining the slide valve with the piston D, by means of a roller G,attached to the valve, and a bar H, attached to the said pistonsubstantially as and for the purpose herein specified.

JACOB MARTIN.

GEO. E. LoUNsBURY.

